Prosecutors set the stage Friday for a courtroom fight over the mental health of a Southern Utah teen accused of attempting to bomb a St. George high school and vandalizing a separate school with ISIS-themed graffiti.

Friday's testimony was part of an ongoing hearing in a juvenile court proceeding to determine whether the 16-year-old boy should be tried as an adult in the case. He has been charged with felony counts of attempted murder and use of a weapon of mass destruction, as well as misdemeanor counts of graffiti and abuse of a flag.

In mid-June, prosecutors showed a video recording of the teen's interview with St. George police in which he admits he was responsible for the incidents at Pine View High on March 5 and Hurricane High on Feb. 15.

Saatoff said he saw discrepancies in the Southern Utah case. The autistim diagnosis and perceived intellectual limitations don’t seem to make sense given the specifics of the alleged crimes, he said, arguing they required meticulous planning and duplicitous behavior.

Saatoff said he was also struck by the boy’s lifetime of generally good school grades, strong family support system, and relative lack of problems.

Then, having secretly researched Islamic State ideology and studied how to build an explosive device using items from inside his home, he took the incendiary device with him to Pine View High, where he left it in a lunchroom full of approximately 75 to 150 students, Saatoff testified.

Through it all, he avoided detection and hid his involvement, up until police confronted him with visual evidence taken from cameras inside the high school, Saatoff said.

The teen's internet history and responses in interviews suggested he was also very cognizant of the way the initial incident had been received, Saatoff testified, noting the boy had said that he wanted to "leverage" the national attention around a school shooting in Parkland, Florida, in mid-February to create fear in the second incident.

“I was struck by the fact a 16-year-old ... was able to fool those around him before, during and after these events," Saatoff said.

He argued that none of the elements of the boy's actions matched the general behavioral tendencies of somebody with autism spectrum disorder.

However, he stopped short of saying he outright disagreed with the diagnosis, only saying he would want to know more about the boy.

At one point he said he would have concerns about being able to gauge whether the boy would be a threat if put back into the community.

“How do we know someone like (the boy) is planning an event?" he said, referencing the behavior that led up to and immediately followed the two incidents. "Certainly his outward demeanor did not suggest to those around him that something was wrong and there was a concern.”

His parents also took the stand Thursday, testifying that the boy had struggled to get along with others at times throughout his life, and that he had complained of bullying at various times. In the middle of the school year he left Hurricane High after an alleged bullying incident in one of his classes.

Defense challenges witness

Defense attorney Stephen Harris questioned Saatoff's ability to weigh in on the case, as he had neither interviewed the boy nor did he have any specialization in cases of autistic juveniles. The defense moved to have his testimony stricken, arguing that Saatoff himself had acknowledged that a specialist would be better equipped to actually diagnose autism spectrum disorder.

Judge Paul E. Dame said he would take those factors into consideration, but he ruled to keep Saatoff as an expert witness. Prosecutors said they hadn't brought Saatoff in to testify solely to the autism spectrum disorder diagnosis, noting that he is an expert in clinical psychology and threat analysis.